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  #1391  
Old 05-06-12, 12:47
coapman coapman is offline
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Originally Posted by acoggan View Post
On the contrary: pedaling is an extremely "natural" motion, in that 1) we activate the same muscles in essentially the same sequence as when walking or running, and 2) even pedaling backwards has very little effect on this pattern. IOW, we pedal using essentially the same evolutionarily-designed motor program as we use during upright bipedal locomotion, with very little learning either necessary or beneficial.


Correct, your objective in natural pedaling is to apply a vertically downward force to the pedals. Nothing could be easier and so it continues today. What you are forgetting is that this natural motion was established at a time when cleats were unheard of and it was only possible to apply torque in that manner. Cleats provide the medium for delivering highly effective forward force to the cranks as they move through 12 o'c. How are the muscles used to generate this maximal forward force:: If you stand with your back against a wall and then slide downwards to an almost seated position. You then apply a force to that wall as if attempting to force it backwards, using one leg at a time. On the bike you need resistance to counteract this force and this is where the arms come into the action. You also need the correct bike set-up, but it's as simple as that.
  #1392  
Old 05-06-12, 13:01
coapman coapman is offline
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Originally Posted by coapman View Post
Correct, your objective in natural pedaling is to apply a vertically downward force to the pedals. Nothing could be easier and so it continues today. What you are forgetting is that this natural motion was established at a time when cleats were unheard of and it was only possible to apply torque in that manner. Cleats provide the medium for delivering highly effective forward force to the cranks as they move through 12 o'c. How are the muscles used to generate this maximal forward force:: If you stand with your back against a wall and then slide downwards to an almost seated position. You then apply a force to that wall as if attempting to force it backwards, using one leg at a time. On the bike you need resistance to counteract this force and this is where the arms come into the action. You also need the correct bike set-up, but it's as simple as that.
I forgot to mention that when attempting to apply that force to the wall, you keep the entire sole of your shoe on the ground.
  #1393  
Old 05-07-12, 14:19
FrankDay FrankDay is offline
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Two crank length anecdotes to report from this weekend.

1. Racing in his first ever bike race Mike Clark won it using 145 cranks.

2. Dave Campbell won his age group at the Wildflower Olympic distance triathlon using 200mm cranks. He is 6'5" though, which helps.

How much did the crank length they choose help or hurt their performances is unknown but a win is a win and I'll bet both are very happy with their choice.
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  #1394  
Old 05-07-12, 14:30
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Here is another crank length anecdote from this weekend. Did my first expo of the year at the Wildflower triathlon.

For awhile now I have set my crank length on my demo bicycles to 145 to make it easier for potential customers to have success in pedaling the product but long enough that if feels like regular pedaling but let most still still experience having a lot of difficulty. I had two bikes set up and I decided to set one up with 130 cranks and then have customers to ride both and see if they could tell me which one was easier and if they could tell what the difference was.

1. about 90% of them said the 130 were easier right away. 100% said the 130 were easier when comparing being in the aero position.

2. None could guess or feel difference between the cranks until I told them.

I thought it a particularly good demonstration as to why they ought to be experimenting with crank length.
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  #1395  
Old 05-07-12, 17:54
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Originally Posted by FrankDay View Post
I thought it a particularly good demonstration as to why they ought to be experimenting with crank length.
About as much use as shuffling the deck chairs on the Titanic when compared to the real research that has been performed on crank length.
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  #1396  
Old 05-07-12, 19:49
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Originally Posted by CoachFergie View Post
About as much use as shuffling the deck chairs on the Titanic when compared to the real research that has been performed on crank length.
Yes, but Frank has some nice shiny new adjustable PowerCranks that will make it sooooooooo easy to do the experiment Gosh fun science for everyone!


Hugh
  #1397  
Old 05-08-12, 01:03
FrankDay FrankDay is offline
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Originally Posted by sciguy View Post
Would that be Courtney Ogden who has seemed to be suffering from a series of knee injuries for the past several years? Several of us are wondering if his injuries might relate to the use either PowerCranks, shorter cranks or both.

YMMV,

Hugh
Of course I don't know all the details but I have told Courtney over and over that he pretty much needs to stop running (and the use the PC's maintain his running fitness) until he is completely healed. It seems, he, like many, believe that one must run a lot to run well so he has, I believe, pretty much ignored my advice here. I think though he may finally be paying attention. The only injury the PC"s can cause in an athlete is an overuse injury from trying to do too much too fast. That isn't an issue with Courtney. Nothing slows an athlete down more than an injury.
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  #1398  
Old 05-08-12, 01:12
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Originally Posted by acoggan View Post
1. The subjects in Jim's studies were all experienced cyclists, who were free to adopt whatever thigh-torso angle they felt allowed them to generate maximal power for a very short duration while seated (naturally, I had my hands in the drops). I would therefore argue that it is quite likely they did so, i.e., "body wisdom" is a powerful influence...this is, after all, why you see pursuiters invariably creeping onto the nose of their saddle late in race, or (more relevantly) why steep-seattube-angled TT/tri bikes were invented in the first place. Thus, while it is possible that cranks even shorter than 145 mm might (or might not) be better when a rider is forced to assume an overly-acute thigh-torso angle, that is really putting the cart before the horse...the goal is to maximize power:CdA, not just minimize CdA, so you never want to adopt a position that compromises your power *unless* you know that the improvement in CdA is worth it.
You can argue whatever you want but the fact remains that Dr. Martin did not measure nor comment on the body position used by his subjects so, it is simply supposition on your part. Even you agree that hip angle at TDC can affect power. Hip angle changes as one goes lower in front and it can affect power. You write above: "the goal is to maximize power:CdA". Someone needs to do a study on this, don't you think?
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2. In keeping with the above, I have measured my both my CdA and my sustainable power in a wide range of aero of positions while using a wide range of crank lengths. What I have found is that if I go too low, my power drops more than my CdA, and shortening the cranks by up to 22 mm doesn't help.
Thanks for that anecdotal report as it applies to you. I seem to be getting a lot of reports to the contrary. Wouldn't it be nice if we knew what "science" says about how this might apply to a wider population.
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Last edited by FrankDay; 05-08-12 at 03:23.
  #1399  
Old 05-08-12, 01:30
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Originally Posted by acoggan View Post
On the contrary: pedaling is an extremely "natural" motion, in that 1) we activate the same muscles in essentially the same sequence as when walking or running, and 2) even pedaling backwards has very little effect on this pattern. IOW, we pedal using essentially the same evolutionarily-designed motor program as we use during upright bipedal locomotion, with very little learning either necessary or beneficial.
Let me get this straight. Are you saying that just because life on earth evolved to efficiently do repetitive reciprocal antagonist muscle activation to efficiently walk, chew, wing flap, or run that cycling is "natural" because we get to invoke that spinal reflex?

But, to go a step further, are you saying that because people learn to use, essentially, the same pattern in cycling that we do in walking or running, that this means this has to be the most efficient cycling pattern simply because it is related to the most efficient running or walking pattern? If so, do you have any studies that back up this contention? Really? Why on earth would a pattern (walking/running) that only allows actual propulsive force application for 0.2-0.5 of the time be optimal for an "invented" pattern that allows power application for 100% of the time? Adapting the walking/running pattern is, of course, the "easy" and obvious way to go if one wants to learn to cycle. There is, of course, zero evidence it is the best or only way to go if one wants to optimize the method.
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Last edited by FrankDay; 05-08-12 at 01:34.
  #1400  
Old 05-08-12, 02:38
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Quote:
Originally Posted by FrankDay View Post
Here is another crank length anecdote from this weekend. Did my first expo of the year at the Wildflower triathlon.

For awhile now I have set my crank length on my demo bicycles to 145 to make it easier for potential customers to have success in pedaling the product but long enough that if feels like regular pedaling but let most still still experience having a lot of difficulty. I had two bikes set up and I decided to set one up with 130 cranks and then have customers to ride both and see if they could tell me which one was easier and if they could tell what the difference was.

1. about 90% of them said the 130 were easier right away. 100% said the 130 were easier when comparing being in the aero position.

2. None could guess or feel difference between the cranks until I told them.

I thought it a particularly good demonstration as to why they ought to be experimenting with crank length.
So until they had some outside information steering them towards a certain outcome, they had no idea that there was any difference? For a guy who talks a lot about science, you ought to know what that means.
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